No, they're speaker terminals like the ones on the back of an AVR.
If you're using an older AVR that doesn't have a subwoofer output, you normally run speaker wire:
- from the L+R speaker-level outputs on your AVR to the L+R speaker-level inputs on the sub; and
- from the L+R speaker-level outputs on the sub to your L+R speakers.
And then you use the sub's high-cut / low-pass filter (a.k.a. the crossover) to blend the sub with your mains.
I'm wondering because:
- I don't ever recall seeing AVR and speaker manufacturers trending away from using speaker-wire terminals.
- With the advent of AVRs with dedicated subwoofer outputs and bass management, while some manufacturers have dropped speaker-level connections on their subs in favour of line-level connections only, there are still many brands and models out there that have both.
Those are what are known as 5-way binding posts. The open center hole is for banana plugs, the plastic unscrews with a through hole for wire or pins, or you can sandwich down thicker wire or spade lugs.
Most speaker-wire terminals I see now are larger in diameter and look a little different, but that design was common for a long time.